Substrate loading and unloading station with buffer

ABSTRACT

A substrate processing apparatus having a station for loading and unloading substrates from the apparatus, includes an aperture closure for sealing a loading and unloading aperture of the station, apparatus for removing a door of a substrate magazine and thus opening the substrate magazine, and for operating the aperture closure to open the aperture, and an elevator for precisely positioning the open substrate magazine along a vertical axis within a usable range of motion. The station may also include a sensor for mapping locations of the substrates, and a mini-environment for interfacing the station to a substrate processing system.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention is directed to a loading and unloading station forsubstrates with one or more magazines that serve as a substrate buffer.The invention is capable of mapping features of the substrates andindexing the substrates in a Z-axis direction.

[0003] 2. Brief Description of Related Developments

[0004] To minimize process defects, substrate processing equipmentmanufacturers have attempted to prevent particles from reaching thesubstrates. Systems have been designed to isolate substrates fromparticles during storage, transport and transfer into processingequipment. The Standard Mechanical Interface (SMIF) system has beendevised and used to reduce particle contamination by significantlyreducing particle fluxes onto substrates. This has been accomplished bymechanically ensuring that during transport, storage and processing ofthe substrates, the gaseous media (such as air or nitrogen) surroundingthe substrates is essentially stationary relative to the substrates andby ensuring that particles from the ambient outside environment do notenter the immediate internal substrate environment.

[0005] A typical SMIF system utilizes minimum volume, dust proof boxesor carriers for storing and transporting open rack substrate cassettes.The carriers have doors designed to mate with doors on interface portson the substrate processing equipment. In a typical SMIF system, acarrier is positioned at the interface port and the carrier and portdoors are opened simultaneously. A manipulator may then individuallyremove the substrates and transport them to a load lock for processingin a vacuum system.

[0006] The SMIF box is bottom loading design and is generally used tocarry substrates sized to a diameter of 200 mm. More recently, carriershave been developed that are of the front opening unified pod (FOUP)design, intended to carry larger substrates.

[0007] Present carrier systems typically couple a single carrier to thesubstrate processing system at a time. It would be advantageous toprovide a substrate loading and unloading system capable of interfacinga number of carriers to the substrate processing system, allowing alarger number of substrates to be processed before the carriers must beemptied and refilled.

[0008] With either a cassette or FOUP carrier, a front end is typicallyprovided between the carrier and the substrate processing equipment toalign each substrate and/or to place each substrate at a specific XYZlocation for access by a transport apparatus or robot. It would beadvantageous to provide a substrate loading and unloading system capableof determining the locations of substrates and features of thosesubstrates within each carrier. It would also be advantageous to providea substrate loading and unloading system capable of placing a substrateat a specific XYZ location. These features could allow such a substrateloading and unloading system to be coupled directly to a substrateprocessing system, eliminating the need for a front end for substratealignment or placement.

[0009] In light of the foregoing state of the art the present inventionhas been conceived and is now reduced to practice.

SUMMARY OF THE INVENTION

[0010] A substrate processing apparatus having a station for loading andunloading substrates from the apparatus, includes an aperture closurefor sealing a loading and unloading aperture of the station, apparatusfor removing a door of a substrate magazine and thus opening thesubstrate magazine, and for operating the aperture closure to open theaperture, and an elevator for precisely positioning the open substratemagazine along a vertical axis within a usable range of motion. Theelevator operates such that a substrate within the open magazine ispositioned substantially in a wafer transport plane, and is thusaccessible by a transport apparatus. In one embodiment, the elevatorincludes a device for positioning the open substrate magazine such thatsubstantially no vertical movement is required by the transportapparatus. The station also includes a buffer transport for positioningone or more substrate magazines along a second axis oriented in a seconddirection, and a sensor for mapping vertical locations of thesubstrates. The station may also include a shuttle for transporting theone or more magazines along a third axis oriented in a third direction,and a mini-environment for interfacing the station to the substrateprocessing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing aspects and other features of the present inventionare explained in the following description, taken in connection with theaccompanying drawings, wherein:

[0012]FIG. 1 is a top plan diagrammatic view of a substrate processingsystem embodying the present invention, with the cover removed from thetransport chamber;

[0013]FIG. 2 shows a schematic side view of a substrate station inaccordance with the present invention;

[0014]FIG. 3 shows an example embodiment of a magazine;

[0015]FIG. 4 shows a cross sectional view of a magazine;

[0016]FIG. 5 is a diagram of an example substrate;

[0017]FIGS. 6A and 6B show an aperture closure in an extended andretracted position, respectively;

[0018]FIG. 7 shows a schematic top view of the substrate station;

[0019]FIG. 8 shows a schematic side view of the substrate stationillustrating a stroke of an elevator; and FIG.

[0020]FIG. 9 shows a schematic side view of the substrate stationillustrating an operation of a transport apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Referring to FIG. 1, a perspective view of a system 100,incorporating features of the present invention, is illustrated.Although the present invention will be described with reference to theembodiment shown in the drawings, it should be understood that thepresent invention can be embodied in many alternate forms ofembodiments. In addition, any suitable size, shape or type of elementsor materials could be used.

[0022] As shown in FIG. 1, the system 100 is generally a substrateprocessing system for processing substrates. The substrates may include200/300 mm wafers used in semiconductor manufacturing, panels used inthe manufacture of flat panel displays, or any other desired type ofsubstrates. The substrate processing system 100 includes one or moreprocessing modules 105 for performing operations on substrates such asimaging, plasma etching, and the like. It is typical for the processingmodules 105 to be arranged about a closed locus as indicated by a dashedline 110.

[0023] A transport apparatus 115 is centrally disposed within atransport chamber 120 for transferring substrates among the one or moreof the processing modules 105. Transport chamber 120 is preferablymaintained substantially at a vacuum to prevent contamination ofsubstrates while they are transported among processing modules 105. Itshould be understood that transport chamber 120 may contain any otherdesired atmosphere for processing substrates. The substrate processingsystem 100 preferably includes appropriate systems and plumbing (notshown) for generating, and maintaining the desired atmosphere intransport chamber 120. For example, a vacuum pump (not shown) may beconnected to transport chamber 120 using suitable plumbing to draw adesired vacuum condition in transport chamber 120. The vacuum pump maybe regulated by a controller using appropriate monitoring and controldevices (not shown) such as pressure gauges and valves.

[0024] Isolation valves 125 are individually provided at the interfacesof the one or more processing modules 105 and the transport chamber 120.Isolation valves 125 may comprise slot valves, solenoid valves,hydraulic valves, or any other suitable valves that are capable of beingindividually opened and closed, and that when closed, form asubstantially airtight seal between the transport chamber 120 and thecorresponding processing module.

[0025] Each processing module 105 may include one or more systems forprocessing substrates, for example, sputtering, coating, etching,soaking, or any other suitable process for substrates deposited in therespective processing modules. Each processing module 105 may alsoinclude additional isolation valves (not shown) that allow communicationwith other equipment, or substrate processing by other equipment.

[0026] Transport apparatus 115 typically includes a drive section 130and one or more end effectors 135. A preferred embodiment of transportapparatus 115 is described in U.S. Pat. No. 5,180,276, incorporated byreference in its entirety. Drive section 130 may be capable ofpositioning end effector at any desired XYZ location within transportchamber 120 or may provide limited positioning capabilities, forexample, only in the X and Y directions. Drive section 130 is preferablyoperable to move end effector 135 along a wafer transfer plane asdescribed in greater detail below.

[0027] Substrate processing system 100 also includes a substrate loadingand unloading station, or loadport, referred to herein as a substratestation 140, in accordance with the present invention. Substrate station140 is preferably sealingly positioned in close contact with transportchamber 120 such that transport apparatus 115 may access substratesconveyed by substrate station 140. FIG. 2 shows a side view and FIG. 6shows a top view of the substrate station 140.

[0028] Substrate station 140 has a frame 205 for supporting itscomponents and one or more magazines 210. For purposes of this inventiona magazine will be understood to include a cassette, a FOUP, or anyother substrate carrying device that positions or holds substrates in aspaced arrangement. In this embodiment, magazine 120 is shown as a FOUPfor example purposes only.

[0029]FIG. 3 shows an example of magazine 120. Magazine 120 includes ahousing 300 and a magazine opening 310 for providing access to theinterior thereof and for receiving a magazine door 315. Magazine door315 in this example includes a generally rectangular plate 320 with aperipherally extending continuous flange 325. A seal 330 is interposedbetween flange 325 and magazine opening 310.

[0030] When magazine door 315 is positioned in magazine opening 310,flange 325 firmly engages seal 330 to seal the interior of magazine 120from the surrounding atmosphere. A plurality of latch members 335 areprovided on magazine door 315 at peripherally spaced locations forlocking the carrier door 315 in place in magazine opening 310. Latchmembers 335 are movable between an extended, locking position as shown,and a retracted, release position. Latch operating mechanisms 340 areoperably connected to latch members 335 for moving the latch membersbetween the locking position and the release position. Latch operatingmechanisms 340 may be connected by, or may be comprised of, linkages,solenoid devices, or other appropriate apparatus.

[0031]FIG. 4 shows a cross sectional view of magazine 210. In thisembodiment, magazine 210 includes a mounting manifold 410 which issuitably mounted on, and projects upwardly from a magazine base 415. Aplurality of vertically spaced support plates 420 are integral with themounting manifold 410 and project away from the mounting manifold andlie in equally spaced parallel planes. The spacing between the supportplates 420 may be substantially greater than the thickness of asubstrate 425, and each support plate 420 is preferably adapted tosupport a substrate 425 on upper surfaces 435 of substrate supports 440in a generally horizontal plane.

[0032]FIG. 5 shows an example of substrate 425. As mentioned above,substrate 425 may be a silicon planar substrate, a wafer, a flat paneldisplay, or the like. Substrate 425 may have a peripheral edge 510 withany number of features including a fiducial 515.

[0033] Returning now to FIG. 2, substrate station 140 includes a shield290 having an aperture 270 for loading and unloading substrates.Aperture 270 is preferably surrounded by a seal 275, against whichmagazine opening 310 may sealingly abut. When magazine opening 310 is inabutting relationship with seal 275, aperture 270 is aligned withmagazine opening 310.

[0034] Substrate station 140 has a magazine door drive 235, shown in aretracted position, for sealing aperture 270 when magazine opening 310is not abutting seal 275, and for coupling to and removing magazine door315 when magazine opening 310 is abutting seal 275. Magazine door drive235 includes an aperture closure 230 mounted on an extendable member 280which is operated for both translation and pivoting movement by magazinedoor drive 235. When in an extended position, as shown in FIG. 6A,aperture closure 230 seals aperture 270. Returning to FIG. 2, apertureclosure includes a door transport 285 for operating latch operatingmechanism 340 (FIG. 3) so as to lock or release magazine door 315 frommagazine 210 and to support magazine door 315 during translation andpivoting movements. Door transport 285 includes selectively operabledoor supports (not shown) which are engageable with magazine door 315when magazine opening 310 is in abutting relationship with seal 275.Magazine 210, shield 290, aperture 270, and magazine door drive 235 arepreferably located proximate a central area 265 of substrate station140. In alternate embodiments, the area in which magazine 210, shield290, aperture 270, and magazine door drive 235 are located may not becentral.

[0035] Substrate station 140 also includes provisions for interfacing toan isolation valve 240 which couples substrate station 140 to transportchamber 120. Isolation valve 240 is positioned to allow substrates to betransported along a wafer transfer plane 265 between magazine 210 andtransport chamber 120.

[0036] Substrate station 140 additionally includes an elevator 215 formoving magazine 210 in a Z-axis direction. Elevator 215 may comprise ashelf 237 for supporting magazine 210, attached to a drive 242, whichmay be a ball screw, belt drive, linear motor, or any other suitabledevice for supporting magazine 210 and providing vertical movement inaccordance with the teachings of the invention.

[0037] Elevator 215 is operable to precisely move magazine 210. In thecontext of the present invention, “precisely move” means to repeatablyposition a substrate 425 held in magazine 210 within a usable range ofmotion. In one embodiment, elevator 215 is capable of repeatablypositioning a substrate held in magazine 210 within at least 0.05 mm.

[0038] Elevator 215 is operable to precisely move magazine 210 toposition each substrate 425 held in magazine 210 substantially in wafertransfer plane 265. In another embodiment, elevator 215 is operable toprecisely move magazine 210 to position an upper surface 430 of anysupport plate 420 (FIG. 4), an upper surface 435 of any substratesupport 440 (FIG. 4), or other location in the interior of magazine 210,substantially in wafer transfer plane 265. In still another embodiment,elevator 215 is preferably operable to move magazine 210 to place eachsubstrate 425 held in magazine 210 at any desirable Z axis position. Inyet another embodiment, elevator 215 is preferably operable to movemagazine 210 in a way to place each substrate 425 held in magazine 210at any desirable Z axis position accessible by transport apparatus 115.Because of the precision placement capabilities of elevator 215, atransport apparatus may be employed in substrate processing system 100that has limited or no Z axis capability.

[0039] Substrate station 140 also includes a shuttle 220 for movingmagazines along the Y-axis, and a buffer transport 225 for movingmagazines in an X-axis direction. Substrate station 140 further includesa sensor 245 for mapping substrates and a mini-environment 250 forisolating the interior of magazine 210 from the surrounding atmosphere.Substrate station 140 may be mounted on a carriage 260 allowingsubstrate station 140 to move in the Y or X direction.

[0040] Turning now to FIG. 7, buffer transport 225 is adapted to movethe one or more magazines 210 along the X-axis. Buffer transport 225 maybe any suitable mechanism for transporting magazines 210 along the Xaxis, but is preferably a shelf 610, guided by a rail 615 aligned withthe X axis, coupled to a drive mechanism 620. Buffer transport 225 mayinclude a screw, belt, carriage, or any type of driving or movementmechanism. In an embodiment where substrate station 140 includes aplurality of magazines 210, 210A, 210B, magazines 210A, 210B function asone or more substrate buffers, thus enabling the temporary storage orholding of substrates 425 either before or after processing. Buffertransport 225 is further operable to move individual magazines to andfrom peripheral areas 650A, 650B and into and out of central area 265.

[0041] Shuttle 220 may include any suitable mechanism for transportingmagazines 210 along the Y axis. Shuttle 220 may also comprise a shelf625 which, in one embodiment, may be shelf 610. Shelf 625 may guided bya rail 630 along the Y axis, and may be coupled to a suitable drivemechanism 635.

[0042] Returning now to FIG. 2, shuttle 220 operates to move the one ormore magazines 210 in a forward Y direction, toward aperture 270, and ina rearward Y direction, away from aperture 270. Elevator 215 is operableto transport one or more magazines 210 vertically in an upward anddownward Z direction. Shield 290 with aperture 270 is operable to movewith elevator 215 and magazine 210 such that when magazine opening 310is sealingly abutting seal 275, aperture 270 remains aligned withmagazine opening 310 during movement of elevator 215. Buffer transport225, shuttle 220, and elevator 215 may operate together to position oneor more magazines at any location attainable within their combined rangeof motions.

[0043] Mini-environment 250 operates to isolate the interior of magazine210 from the surrounding atmosphere while magazine 210 abuts seal 275and magazine door 315 is unlatched and removed. Substrate station 140optionally may include devices and mechanisms (not shown) capable ofgenerating and maintaining an environment inside mini-environment 250having certain characteristics, for example, atmospheric pressure,humidity, presence of certain compounds, etc. The devices and mechanismsmay also be operable to match the environment of mini-environment 250 toanother environment, for example, the environment of transport chamber120. In a preferred embodiment, when isolation valve 240 is closed,mini-environment encloses an atmosphere at or slightly above standardatmospheric pressure, and when isolation valve is open, mini-environmentencloses an atmosphere at the same pressure as transport chamber 120.

[0044] Sensor 245 for mapping substrates is preferably mounted to theframe of substrate transport station 140, inside mini-environment 250.Sensor 245 may comprise one or more distance measuring sensors, laserdisplacement meters, CCD sensors, imaging devices, opto-electronicsensors, capacitive sensors, or any sensor, sensors, or sensor system,suitable for mapping substrates. In a preferred embodiment, sensor 245is a “through-beam” sensor.

[0045] Sensor 245 may be rotated to a retracted position A when not inuse and rotated to position B for scanning or mapping operations aftermagazine opening 310 has been positioned in abutting relationship withseal 275 and magazine door 315 has been removed. Alternatively, sensor245 may be retracted in a linear direction C and advanced to position Bfor scanning. In another embodiment, sensor 245 may be mounted in anyorientation at any location so long as sensor 245 is capable of scanningsubstrates present inside magazine 210. Elevator 215 may then transportmagazine 210 vertically such that substrates 425 within the magazine 210pass in proximity to sensor 245, allowing sensor 245 to scan or mapsubstrates 425. For example, as substrates 425 pass vertically by sensor245, the sensor 245 may record their vertical positions. Optionally,sensor 245 may map the horizontal location, and the location of anynumber of points or features along each substrate's peripheral 510,including the location of the fiducial 515 (FIG. 5).

[0046] Example operations of substrate station 140 are described asfollows with reference to FIGS. 2 and 6-9. In one example, operationsmay begin with aperture closure 230 in an extended position (FIG. 6A),effectively sealing aperture 270. Buffer transport 225 then operates tomove a magazine 210 with a locked magazine door 315 along the X-axisfrom peripheral area 650A or 650B into central area 265. Shuttle 220then operates to move magazine 210 in a forward Y direction untilmagazine opening 310 sealingly abuts seal 275.

[0047] Magazine door drive 235 then operates aperture closure 230 sothat door supports 295 on door transport 285 engage magazine door 315.Once door supports 295 have engaged magazine door 315, door transport285 operates latch operating mechanism 340 to release magazine door 315from magazine 210. Magazine door drive 235 then operates member 280 toremove magazine door 315 from magazine 215 and transport magazine door315 to a lowered position, away from magazine opening 310 (FIG. 6B).U.S. Pat. No. 6,071,059, incorporated by reference in its entirety,describes a typical door removal operation.

[0048] Sensor 245 then rotates to position B. Sensor 245 may be actuateddirectly or indirectly by the action of removing magazine door 315, ormay be actuated independently. Isolation valve 240 may be openedsimultaneously with the removal of magazine door 315, or may be openedat a later time.

[0049] Elevator 215 then vertically moves magazine 210 such that allsubstrates 425 are transported past sensor 245. In a preferredembodiment, shown in FIG. 8, elevator 215 is at least capable of movingshelf 237 from a lower position 710 to an upper position 715. Thevertical position of each substrate 245 is mapped as it passes sensor245. After mapping is complete, sensor 245 may be returned to retractedposition B.

[0050] As shown in FIG. 9, elevator 215 then returns magazine 210 to aknown height in central area 265, positioning a particular substrate 425in wafer transfer plane 265, which is a plane that is accessible bytransport apparatus 115. Isolation valve 240 may be opened at this timeif not previously opened. Transport apparatus 115 may then extend endeffector 135 into magazine 210 to remove substrate 425. Because thesubstrates have been mapped by sensor 245, the location of eachsubstrate 425 is known and elevator 215 may subsequently move magazine210 such that a particular substrate is positioned in wafer transferplane 265 for removal by transport apparatus 115 without any significantZ-axis movement by transport apparatus 115. Transport apparatus 115 maythen replace substrates 425 in magazine 210 in a similar fashion, whereelevator 215 moves magazine 210 such a that a particular support plate420 (FIG. 4) of magazine 210 is situated adjacent wafer transfer plane265, allowing transport apparatus 115 to replace a previously removedsubstrate or to place another substrate in magazine 210. Substratestation 140 may coordinate the movements of elevator 215 with themovements of transport apparatus 115 such that substrates 425 may beremoved from or placed into magazine 210 in any desirable order orlocation.

[0051] When access to magazine 210 is no longer required, Transportapparatus 115 retracts end effector 135 and isolation valve 240 may beclosed while magazine door drive 235 replaces and locks magazine door315. In one embodiment, the action of replacing magazine door 315 maycause sensor 245 to move to retracted position B. When isolation valve240 is closed and magazine door has been replaced and locked, shuttle220 may then operate to move magazine 210 in a rearward Y direction,causing magazine opening 310 to disengage from seal 275.

[0052] Buffer transport 225 may then move magazine 210 to one of theperipheral areas for example, 650B (FIG. 6), and then move magazine 210Afrom peripheral area 650A to central area 265 for processing thesubstrates therein. As mentioned above, buffer transport is capable ofmoving any one of the magazines among peripheral areas 650A, 650B, andcentral area 265 as required for loading, unloading, and processing ofsubstrates.

[0053] Thus, substrate station 140 is capable of holding a buffer ofsubstrates 425 for processing, disposition after processing, or storage.Sensor 245 is capable of mapping the location and features of substrates425 while situated in magazine 210, preferably positioned in centralarea 265. Buffer transport 225, shuttle 220, and elevator 215 arecapable of operating together to position one or more magazines 210, andthus the substrates therein, at any position within their combined rangeof motions. One advantage of these mapping and positioning capabilitiesis the ability to place each substrate at the wafer transfer plane 265,eliminating the need for any significant Z-axis movement by transportapparatus 115. Substrate station 140 is capable of being mated directlyto transport chamber 120, thus eliminating the need for a front end forsubstrate alignment and placement.

[0054] It should be understood that the foregoing description is onlyillustrative of the invention. Various alternatives and modificationscan be devised by those skilled in the art without departing from theinvention. Accordingly, the present invention is intended to embrace allsuch alternatives, modifications and variances which fall within thescope of the appended claims.

What is claimed is:
 1. A substrate processing apparatus having a stationfor loading and unloading substrates from the apparatus, the stationcomprising: an aperture closure for sealing a loading and unloadingaperture of the station; apparatus for removing a door of a substratemagazine and thus opening the substrate magazine, and for operating theaperture closure to open the aperture; and an elevator for preciselypositioning the open substrate magazine along a vertical axis within ausable range of motion.
 2. The substrate processing apparatus of claim1, wherein the elevator operates such that a substrate within the openmagazine is positioned substantially in a wafer transport plane, thesubstrate processing apparatus further comprising a transport apparatusfor accessing the substrate in the wafer transport plane through theaperture.
 3. The substrate processing apparatus of claim 2, wherein theelevator includes a device for positioning the open substrate magazinesuch that substantially no vertical movement is required by thetransport apparatus.
 4. The substrate processing apparatus of claim 1,further comprising a substrate buffer for temporary substrate storage.5. The substrate processing apparatus of claim 1, wherein the stationfurther comprises at least one peripheral area and a central area. 6.The substrate processing apparatus of claim 5, further comprising abuffer transport for positioning one or more substrate magazines along asecond axis oriented in a second direction.
 7. The substrate processingapparatus of claim 6, wherein the buffer transport is operable to placethe one or more magazines in the at least one peripheral area and thecentral area.
 8. The substrate processing apparatus of claim 7, whereinthe elevator is operable to move the one or more magazines placed in thecentral area.
 9. The substrate processing apparatus of claim 1, whereinthe station further comprises a sensor for mapping vertical locations ofthe substrates.
 10. The substrate processing apparatus of claim 9,wherein the sensor is mounted to a frame of the station and an iscapable of mapping the vertical location while the elevator is preciselypositioning the open substrate magazine along the vertical axis.
 11. Thesubstrate processing apparatus of claim 9, wherein the sensor isrotatably mounted on a frame of the station such that upon removal of adoor of the magazine, the sensor extends inside the magazine.
 12. Thesubstrate processing apparatus of claim 1, wherein the station furthercomprises a shuttle for transporting the one or more magazines along athird axis oriented in a third direction different from the first andsecond directions.
 13. The substrate processing apparatus of claim 1,wherein the station further comprises a mini-environment for interfacingthe station to the substrate processing apparatus.